Communication system



J. D. JOHNSTON COMMUNICATION SYSTEM March 15, 1938.

RU 3 9 l 8 2 t p e S d e l 1 F 2 Sheets-Sheet l M P 5 Q U m oz 10 6 I FV U LINE 1 J K L M N 0 P Q R 5 A B c b E F G H 14- M m M l h FIG. 2.

o c Y -ll. v R M o P E u L m M 12113 22 22 22443314423141333444 E R R u c R n r r ABCDEFGHIJKLMNDPQRSTUVWXYZ E CL S L March 15, 1938. J JQHNSTQN 2,111,146

7 COMMUNICATION SYSTEM Filed Sept. 28, 193-5 2 Sheets-Sheet 2 L5 CR L INVENTOR f r f i 1K:

. ATITORNEY nism embodying the invention or from an in- I spection of the accompanying drawings; and the Patented Mar. 15,1938 7 STATES II it John D.

CATll0N SYSTEM Johnston, Binghamton, N. W assignor to International Business Machines @orporation, New York, N. Y., a corporation of New York Application September as, loss, Serial No. taste 6 Claims.

The present invention is in the form of an improvement of the system described in the aforesaid application. Briefly and broadly, the system in said application comprises a transmitting unit to initiate character signals consisting of code combinations of impulses having differential current values and polarity. The receiving unit includes relay devices. sensitive to said impulse characteristics to control the selection of different circuits, for example, a galvanometer relay of the dArsonval type may be used to respond to the, different current values employed and the polarity of the impulses, so

that the relay brush or armature is positioned to engage one of a plurality of contacts in accordance with the characteristics of the character signal. In addition thereto, another relay device may be used to be responsive only to the number of impulses included in the code combinations, in turn, controlling a device such as a relay to be operated step by step such as the well known type'of stepping relay.

A plurality of circuits are associated with the galvanometer relay contacts and with the contacts of the stepping relay and are arran ed so that upon the respective positioning of the galvanometer relay and the stepping relay, a single circuit corresponding to the character signal is selected to be energized effecting registration of the selected character.

An object of the present invention is to provide individual control devices adapted to be responsive successively to the signal impulses and to effect selection of the particular circuits upon each energization thereof in accordance with the signal impulses transmitted.

Various other objects and advantages of the invention will be obvious from the following particular description of one form of mechainvention also constitutes certain new and useful (or. 17mm features of construction and combination of parts hereinafter set forth and claimed.

In the drawings:

Fig. 1 is a schematic diagram showing one form of the connections of the impulse transmitter.

Fig. 2 is a preferred form of the code used in conjunction with the present invention.

Fig. 3 is a schematic diagram showing one form of circuit arrangement of the receiving system.

Referring now to Fig. 1, a plurality of pulse wheels or disks it are shown with a combination of conducting segments it thereon. The arrangement and number of conducting segments for each disk corresponds to the code shown in Fig. 2, for example, the character 8", the code of which is current value I, positive polarity and four impulses, namely, three short impulses and one long impulse. Therefore, on the disk Mfor the character 3, for conducting segments l6 are disposed thereon so that the three short pulses of current are conducted before the long segment.

engages the contacts ll to transmit the long impulse of its corresponding current value.

It is to be noted that for characters represented by a plurality of impulses the last impulse is always a long impulse the significance of which will be understood as the description progresses;

Each disk therefore has disposed thereupon the number of segments to correspond to the number of impulses in its particular code. It is sufficient to mention that upon depression of a character key of the typewriter (not shown) its corresponding disk 44 is released to complete one revolution, thereby conducting the proper increment' of current value, polarity and thenumber. of impulses representing the character, to the connected line network. A further description of the transmitting system may be had by'referring to the said prior application in which the transmitting typewriter and mechanism for releasing the pulse wheels is shown and completely described. Since this mechanism forms no part of the invention,-it is deemed unnecessary to repeat such description.

With reference now to Fig. 3, the code combination of impulses consisting of predetermined characteristics are received .over the line associated with the galvanometer relay 20 and line relay 2|. The galvanometer relay 20 is shown to comprise an energizing coil 22 connected directly across the line and adapted to be energized in accordance with the various current strengths and polarity of the impulses impressed thereupon to control the positioning of the armature 23 with respect to the associated contacts 25. It is to be noted that eight contacts 24 are provided, four contacts corresponding to the four increment current values of positive polarity and four contacts for the four negative current values. The said relay 20 is adjusted so, as to be sensitive to the current strength and polarity of the impulses and not to the number of the impulses transmitted. The short impulses impressed on the coil 22 are not of sumcient duration to properly position or actuate the movable armature 23 to the proper contacts 25. However, the long impulse which is the last impulse transmitted in the selected code is ofsufiicient duration to cause the armature 23 to engage the proper contact 2 1 corresponding to the current value and polarity of the impulses transmitted. Therefore, when and only when the long impulse is transmitted is the relay 2!! energized sufficiently to be properly positioned so that the armature 23 can supply current to the selected circuit connected to the particular contact 24. To continue with the example, for character S the armature 23 is positioned to contact 25--| of the positive group of contacts, upon reception of the last and long impulse of the group of impulses therefor, for it is remembered that the code combination of the said character is four impulses (three short impulses and one long impulse) of the first current value and positive polarity.

The armature 23 upon being properly positioned connects battery to the corresponding relay of the group of relays 25. associated with the particular contact 24. Assuming the armature 23 to be positioned in engagement with contact 24| grounded battery 25 is connected to relay 25-5 energizing said relay and closing the associated contact 27-5. battery 26 then energizes the associated control relay 28-4 thereby connecting a predetermined group of circuits to ground through the now closed contacts a to d. The description will now be set forth to perform a further selection from the said group of circuits so as to select and energize a single circuit thereof, for the example set forth in the present description, the single circuit to be selected corresponds to the character S.

It was mentioned hereinbefore that the relay 2| is sensitive to the number of, impulses only and therefore it is to be understood that it re- .sponds to both the short and long impulses transmitted over the line. Control circuits are provided to be conditioned so that upon the transmission of a first impulse, relay 3| is adapted to be energized and thereby effecting a particular group or further selection from a predetermined group ,of circuits selected by the operation relay 20. Operation of relay 3| conditions a control relay 35 so that upon the receipt of a second impulse, relay 32 is energized and another particular group of circuits is selected. Operation of relay 32 conditions a control relay 36 so that the reception of a third impulse energizes relay 33 and selects a third particular group of circuits and also conditions control relay 3! so that a fourth impulse energizes relay 35 and selects a fourth group of particular circuits to complete a further selection operation.

Assuming now that the relay 2| is energized by the first impulse of the group of impulses included in the code for the character 8". Grounded battery 60 is connected to' contact 4L (now closed), conductor 42, normally closed contact 43, conductor 44, normally closed contact 65, conductor.

grounded relay 3|.

Current from grounded,

66, normally closed contact 5'3, conductor :18 and grounded relay 3|, energizing said relay. Connecting battery 40 to contact 39 also effects a particular group selection of circuits, namely the circuits associated with the common conductor 50. Referring to the code signal for character S it is seen that a single circuit selection is not eifected owing to the fact that the armature 23 is not positioned during the reception of the first impulse of the representive group of impulses.

Operation of relay 3| permits a locking circuit to be established for the said relay as follows: Grounded battery 50 is connected through-normally closed contact 5|, conductor 52, normally closed contact 53, conductor 54, normally closed contact 55, conductor 56, normally closed contact 51, conductor 58, contact 49 now closed and Upon de-energization of relay 2|, that is, upon completion of the transmission of the first impulse of the code combination of impulses, grounded battery 4|] is connected by conductor 59, through normally closed contact 60, conductor 6|, contact 32 (now closed), conductor 63 and grounded relay 35, energizing the said relay. A locking circuit for the last mentioned relay is then established by connecting grounded battery fill through the normally closed contact 5|, contact 55, now closed, and the grounded relay 35.

It will now be evident that energization of relay 2| upon receipt of the second impulse connects grounded battery 50 to relay 32 through contact 5|, conductor 52, normally closed contacts l3 and 95 and contact 65 now closed, energizing relay 32 and also connecting battery to contact 65 and the group of circuits associated with common conductor 56. Again further selection of a single circuit from the last mentioned predetermined group of circuits is not effected, since relay 20 is not responsive to the short pulses transmitted. A locking circuitis established to maintain relay 32 energized as follows: from grounded battery ll], to contacts 5|, 53, 55 and 65. Energization of relay 32 opens the contact 51 to break the locking circuit described for relay 3| causing the said relay to be deenergized. Therefore, upon de-energization of relay 2|, grounded battery 40 is connected to relay 36 throughcontacts 60, 61 and 68 to energize relay 36 and establish a locking circuit for this relay by connecting grounded battery 50 through contacts 5| and 69 and grounded relay 36.

In a like manner, energization of relay 2| upon reception of the third impulse causes the relay 33 to be energized and establish a locking circuit therefor, supplying current to a group of circuits associated with the contact 70, but, as

understood, a further single selection can not be effected at this time. Energization of relay 33 breaks the locking circuit just described for relay 32 and deenergizes the said relay.

Deenergization of relay 2| similarly energizesrelay 3'! and establishes a locking circuit for the said relay which conditions circuits similar to those just described,- so that upon the fourth energization of relay 2| due, to the reception of the fourth signal impulse, battery 4|) is connected through contact now closed to energize relay 34 and establish a' locking circuit therefor through contact 12. Opening of contact 53 breaks the locking circuit for relay 33 causing said relay to be de-energized which is now understood without further description. Grounded battery 40 is then connected through the normally closed contact: 5!, conductor 52, contacts I5 now closed and impressed on the predetermined group of circuits connected to and associated with common conductor i6.

Referring now to the code in Figure 2, the fourth impulse of the code combination for character S is a long impulse, the transmission of which in addition to energizing relay 2i efiecting tioned, it is evident that grounded battery 40 can only be effective to energize and operate a single circuit, namely the circuit corresponding to character S, which is as follows: grounded battery 4!) to normally closed contact 5!, conductor 52, contact 15, now closed, conductor .16, solenoid l8 corresponding to the S solenoid, contact a, now closed, to ground. Referring to the drawing; it is seen that a solenoid I8 is included in each one of the circuits associated with the a to d contacts of the control relays 28; the said solenoids may be associated with a suitable recording or control unit, for example, such as a punch or typewriter and may be connected so that upon energization the key bars of the particular recording unit are depressed accordingly to effect registration of the character. Further description of a suitable recorder is deemed unnecessary because a complete disclosure thereof may be had by referring to the said aforementioned application.

Upon depression of the key bars and operation of therecording unit, common contacts 80 are adapted to be operated. Specific mechanism for this provision is not shown since it is old and well known in the art; one method which has been used heretofore is to provide a common bar beneath the key bars of the typewriter and arranged so that the depression of the character key bars lowers the common bar which in turn causes the common contacts to be closed.

Closure of contacts 80 permits grounded battery M to be connected to relay relay thereby opening the associated contacts 5i. Operation of contacts 5| disconnects grounded battery 80 from the contacts 6%, t9 and 82, through which it must be remembered thelocking circuits for relays 35, 36 and 37 respectively were established. Therefore the said relays are deenergized and returned to the normal condition as shown in the drawings. Similarly, grounded battery do is removed from contact H to break the locking circuit established for relay 3d thereby restoring the-said relay to normal condition. It is evident from the description just set forth that upon operation of the recording unit the conditioned control circuits for the relay selecting unit just described are all restored to the normal condition as shownin the drawings and in a condition to continue subsequent selection of character circuits in accordance with the character signals. From the description just set forth regarding the selective relay circuits it is obvious that if the character code combination includes a number of impulses less than four impulses, the conditioning and operation of the circuits is similar to the op- 38, energizing this eration just outlined and that irrespective of the number of impulses transmitted for the character signal, operation of therecording unit restores the conditioned circuits to normal similarly as described herein.

While there has been shown and described and pointed out the fundamental novel features of the invention as applied to a single modification, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention therefore to be limited only as indicated by the scope of the following claims.

What is claimed is as follows:

1. In a communication system, means to transmit character signals comprising code combinations of impulses having different current values and polarity and number of impulses included in the code, a plurality of circuits, means responsive solely to'the current value and polarity of the impulses to select a predetermined number of circuits from said plurality of circuits and means responsive solely to the number of impulses included in said code to select certain circuits from said plurality upon each energization thereof and to condition control circuits upon deenergization of the last mentioned means to permit further selection from said predetermined number of circuits upon a subsequent energization of said last mentioned means.

2. In a communication system, means to transmit character signals comprising code combinations of impulses having different current values and polarity and number of impulses included in the code, a plurality of circuits, a plurality of control devices, means responsive solely to the number of impulses included in'said code to control the successive energization of said control devices to select predetermined groups of circuits from said plurality of circuits in accordance with the number of impulses in said code, and means responsive solely to the current value and polarity of the impulses to complete a further selection of circuits from said predetermined group of circuits.

3. The invention set forth in claim 2 in which 1 control circuits are provided to maintain the said control devices energized until the reception of the subsequent impulse.

4. In a communication system, means to transmit character signals comprising code combinations of impulses having different current values and polarity and number of impulses included in the code, a plurality of circuits, a plurality of individual relay devices responsive to and conditionedsolely by the number of impulses included in said code to obtain step by step selection of certain groups of circuits from said plurality of circuits and means responsive solely to the current value and polarity of the impulses to complete a further selection of circuits from said groups of circuit.

5. In a communication system, means to transmit signals comprising code combinations of impulses having different current values and polarity and number of impulses included in the code, a plurality of circuits, means responsive to the current value and polarity of the impulses and means responsive solely to the number of impulses included in said code to select a particular circuit from said plurality of circuits, said last mentioned means including a plurality of therefor to obtain step by step circuit selection and to be conditioned during the transmission of the impulses to maintain the selection of the said particular circuit upon completion of the 5 transmission of the' character signal, a receiving device adapted to be operated by said selected circuit, and means to restore the conditioned 

